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Biomedical subjects

M Berry

Publications and source records attributed to M Berry.

At least 289 records · Page 16Linked to original sources
PubMed1986

Cells involved in the immune response. XXXI. The role of the spleen in the primary and secondary immune responses in the normal adult outbred rabbit: the initial localization of memory cells to the spleen and their subsequent dissemination to the thymus and peripheral lymph nodes.

Normal adult outbred rabbits were immunized intravenously (iv) with sheep erythrocytes (SRBC). At varying times thereafter, the different lymphoid organs were investigated for spontaneous and culture-induced antibody secreting cells by the aqueous hemolytic plaque-forming cell (PFC) technique. During the phase of active antibody formation (Days 3 to 30), immediate PFC, indicative of spontaneous antibody synthesis and secretion, were detected principally in the spleen. In the early postimmune memory period (Days 30 to 90), memory cells capable of generating PFC following secondary immunization in in vitro culture with SRBC were detected only in the spleen. However, by 4 months postimmunization, memory cells were detected in the thymus and popliteal lymph node (PLN) as well as in the spleen. The number of memory cells in the thymus and PLN was significantly higher by 6 months postprimary iv immunization and was even further elevated by 9 months postprimary iv immunization. Following in vivo secondary immunization by the iv injection of SRBC 2 or 6 months postprimary immunization, immediate PFC were detected in large numbers in the spleen, the bone marrow, and the blood, marginally in the PLN and not at all in the thymus. Similar results were obtained at 9 months following primary immunization with SRBC with the exception that large numbers of immediate PFC were detected in the PLN following secondary iv immunization. Following culture of these lymphoid cells for 5 days in vitro with SRBC, the thymus and PLN cells, as well as the spleen cells, generated large numbers of PFC. Since immediate PFC were never detected among the freshly isolated thymus cells whereas thymic cell cultures 6 and 9 months postprimary iv immunization invariably generated large numbers of PFC following secondary immunization in vitro, the thymus memory cells would appear to be inaccessible to particulate antigen injected intravenously; they can only be detected following activation by the antigen in culture. The PFC generated by thymus memory cells (and spleen and PLN) were totally inhibited by the inclusion of sheep anti-rabbit IgG into the PFC assay. This finding demonstrates unequivocally that the plaques induced by thymus cells, just as the plaques induced by spleen and PLN cells, are antibody mediated and not false plaques. Therefore, the thymic PFC cells must be antibody-secreting B-memory cells since T cells do not synthesize or secrete immunoglobulins.

Animals↗
PubMed1986

Cells involved in the immune response. XXXIII. Antibody-forming cells in the popliteal lymph nodes in the immunized splenectomized rabbit following intravenous immunization and their subsequent dissemination to the thymus.

Rabbits were splenectomized (splx) and immunized intravenously (iv) with sheep erythrocytes (SRBC) 14 days later. At the height of the primary immune response on Day 8 postimmunization, significant numbers of plaque-forming cells (PFC), that is, antibody-forming cells (AFC) synthesizing and secreting antibodies, were detected in the popliteal lymph nodes (PLN) and lesser numbers were detected in the bone marrow and the circulation. No PFC were detected in any of the other lymphoid organs. Rabbits were sacrificed at 1, 2, 6, or 9 months post-primary iv immunization and cell cultures of the lymphoid organs were set up with the antigen, SRBC, to induce secondary immune responses in vitro. Only the PLN cells challenged with SRBC in vitro 1 month post-primary immunization generated PFC and only PLN and thymus cells generated PFC in vitro at the three other challenge periods, thus demonstrating the existence of memory cells in only these two lymphoid organs in the splx rabbits. Following in vivo secondary immunization iv with SRBC 2, 6, or 9 months post-primary iv immunization. PFC were consistently detected only in the PLN and the bone marrow and inconsistently in the circulation. No PFC were detected in the thymus or in any of the other lymphoid organs. Paradoxically, neither the bone marrow nor the circulating mononuclear cells of these rabbits generated PFC during in vitro culture with SRBC, whereas the thymus cells and the PLN cells generated many PFC in culture with SRBC. These results demonstrate that the thymus contains memory cells following primary immunization of the splx rabbit which are not accessible to particulate antigens injected intravenously, possibly due to a blood-thymus barrier to particulate antigen, and therefore cannot be activated in vivo into secondary antibody formation. The results also indicate that the AFC detected in the circulation and in the bone marrow following primary iv immunization, which do not generate PFC in antigen-stimulated cultures in vitro, are degenerating cells whereas the AFC in the PLN and thymus, which generate many PFC in antigen-stimulated cultures in vitro, constitute the noncirculating precursors of the long-lived memory cells in the splx rabbit. This role of the thymus and PLN as reservoirs for memory cells in the immunized splx rabbit is not influenced by nor is it a result of splx since the thymus and PLN have both been shown to be the major sources of memory cells, along with the spleen, in the immunized nonsplx rabbit.

Animals↗
PubMed1986

Vertex analysis of neural tree structures containing trichotomous nodes.

Vertex analysis defines dichotomous networks in terms of the relative frequencies of pendant (Vp) and nodal (Vd) vertices. Va, Vb and Vc comprise the 3 classes of Vd which connect 2, 1 and 0 Vp respectively. The vertex ratio (VR) of Va/Vb may be used to define topology since Va and Vc approach equality in large networks. The introduction of trichotomous nodes (Vt, comprising Va', Vb', Vc' and Vd', connecting 3, 2, 1 and 0 Vp) confounds vertex analysis in as much as the values of VR must be recalculated to maintain the definition of topology. Each Vt is equivalent to 2Vd. Va', Vc' and Vd' may be unequivocally transformed into Va + Vb; Vb + Vc; and 2Vc respectively. However, Vb' potentially contains Va, Vb and Vc in proportions which must be arbitrarily set, since the mode of growth only determines the frequencies of Vt and not their transformation into Vd pairs. We have assumed that all possible pairs of transformed Vb' are equally likely and, accordingly, Vb' is equivalent to Va/3 + 4Vb/3 + Vc/3. The values of VR for different modes of growth, featuring different frequencies of Vt, may thus be obtained by computer growth simulation. The mode of growth of observed networks may thereby be ascertained from VR, providing all Vt are detectable in the tree.

Dendrites↗
PubMed1986

Neurogenesis and gliogenesis in the human brain.

The primary germinal neural epithelium lines the ventricular system of the brain and shows intense mitotic activity. Neuroblasts migrate from a juxtaluminal position to establish neural centres and, when this task is completed, the definitive ependymal epithelial lining of the ventricles develops, shifting the remnants of the germinal epithelium to a subendymal location. The subendymal layer continues to proliferate giving rise to glia in the postnatal brain. Premature arrest of migration of neuroblasts leads to the accumulation of heterotopic nests anywhere along the migratory path. Within such ectopia, neurons may make normal connections or they may remain undifferentiated and later become tumorigenic. The subependymal layer has long been considered the site of original of periventricular gliomas. Some migrating neuroblasts establish secondary germinal centres far removed from the ventricular system. An example of this is the external granular layer of the cerebellum which, in man, persists for the first 6 months of life. Cerebellar neuroblastomas could originate directly from this layer in the neonate, or from remnants of this layer in older individuals.

Animals↗
PubMed1986

Destruction of meningeal cells over the newborn hamster cerebellum with 6-hydroxydopamine prevents foliation and lamination in the rostral cerebellum.

Intracisternal injection of 30 micrograms 6-hydroxydopamine was used to destroy meningeal cells in the newborn hamster. After 20 or 30 days the cerebella of treated animals showed severe morphological alterations including: an absence of distinct folia anterior to the primary fissure; a disruption of lamination in the same region by the displacement of both Purkinje cells and cerebellar interneurons; a reduction in size and frequency of branching of the medullary tree with anomalous anterobasal branches and splaying; reductions in the area of the molecular layer, the total area occupied by granule cells, the length of the pial surface and the length of the Purkinje cell layer of 29, 21, 57 and 27%, respectively; disorganization of the radially organized glial scaffold by outgrowth of Bergmann glial fibers and displacement of their cell bodies, the Golgi epithelial cells, and anomalous orientation, polarity, size and branching frequency of Purkinje cell dendritic trees. These findings support our earlier hypothesis that the initial destruction of meningeal cells destabilizes the cerebellar surface (basal lamina and glia limitans superficialis) and disorganizes the glial scaffold, while the neuronal cerebellar malformations are secondary to this glial defect.

Aging↗
PubMed1986

Influence of caffeine on exercise performance in habitual caffeine users.

The effect of caffeine on the exercise responses of six women habituated to caffeine (greater than 600 mg/day) was examined during 1-h running at 75% VO2 max on a motorized treadmill. Each subject completed a placebo (PL) and a caffeine ingestion (CC) trial while maintaining normal caffeine intake. The subject then abstained from caffeine for 4 days and again ran after receiving caffeine (CW). Caffeine dosage for all trials was 5 mg/kg body weight. Ingestion of caffeine after withdrawal (CW) resulted in the greatest physiologic effects. Exercise oxygen uptake was significantly elevated by 0.17 l/min over the PL and CC trials (P less than 0.05). The CW trials resulted in an overall R value of 0.79 +/- 0.04 compared with 0.85 +/- 0.08 for the PL and 0.83 +/- 0.04 for the CC trials. Caffeine had its greatest effect on the resting free fatty acid levels after withdrawal: 1104 +/- 425 mu Eq/l compared with 543 +/- 288 for the PL and 839 +/- 526 for the CC. Postexercise lactates were similar for all trials. Post-exercise plasma norepinephrine and dopamine were the highest after the CW trials. The results suggest that habitually high caffeine users acquire a tolerance to caffeine which reduces its effects during prolonged exercise. Furthermore, to magnify the effect of caffeine, habitual users should withdraw from caffeine use for about 4 days.

Adult↗
PubMed1986

The nerve cell.

Explore the source record for details and available documents.

Animals↗
PubMed1985

Derivation of cerebellar Golgi neurons from the external granular layer: evidence from explantation of external granule cells in vivo.

The present report provides evidence to challenge the traditional view that cerebellar Golgi cells are derived from the ventricular neuroepithelium, postulating instead that they originate from external granule cells. Supporting evidence for this assertion comes from three sources: 1) Typical Golgi cells are found in ectopic granule cell colonies, both outside the cerebellum (in the subarachnoid space) and also within the cerebellar cortex between fused folia. Because ectopic granule cell colonies are derived from external granule cells, which become displaced after treatment with 6-hydroxydopamine (6-OHDA), it was assumed that the ectopic Golgi cells also stem from such displaced external granule cells. 2) In order to demonstrate that Golgi cell precursors migrate from the external granular layer into the Purkinje cell plate, the development of the cerebellar cortex was studied over the period of Golgi cell genesis. On E19 the external granular layer in the rat is subdivided into an outer proliferative and an inner subproliferative zone. At the inner margin of the external granular layer, and in the marginal zone, radially oriented, darkly staining cells are present that exhibit all the characteristics of migrating neurons possessing a leading process oriented toward the Purkinje cell plate, a somatic cilium, and a close association with radial glia fibers. In later stages, these cells are also found deep to the Purkinje cell plate. Because Golgi cells arise during the period between E19 and postnatal day 2 in the rat (Altman and Bayer, '77, '78) and as the basket cells, the first neurons of proven origin from the external granular layer, are not produced before the second postnatal day (Altman, '72), the earlier migrating neurons are presumed to be Golgi cells. 3) Available data from cell kinetic 3H-thymidine studies show that there is no unequivocal evidence for Golgi cell genesis from the ventricular neuroepithelium, because, at the time of Golgi cell birth, ventricular and external granular stem cell populations are proliferating, and with the present methods it is not possible to decide which of these are the precursors of Golgi cells. Thus, taken together, the findings of this study show that Golgi cells are more likely to arise from the external granular layer than from the ventricular neuroepithelium. This concept would unify cerebellar histogenesis by proposing that projection neurons arise from the ventricular neuroepithelium, whereas all interneurons of the cerebellar cortex are descendants of the external granular layer.

Animals↗
PubMed1985

Observations on the astrocyte response to a cerebral stab wound in adult rats.

The temporal and spatial distribution of immunocytochemically identified reactive astrocytes is described following a cerebral stab wound in adult rats. Different patterns of reactivity were observed in the cerebral cortex, the corpus callosum and the deep structures of the hemisphere. In the cerebral cortex, the zone of astrocytic reactivity was initially limited to the vicinity of the wound but spread with time to encompass the entire ipsilateral cortex, then regressed; in the deep structures only a spreading phase was observed and this was slower than in the cortex; reactivity in the corpus callosum was slight and always restricted to the immediate vicinity of the lesion. Reactive astrocytes were never observed in the hemisphere contralateral to the lesion. The reorganization of reactive astrocytes in the immediate vicinity of the lesion into a membrana gliae limitans accessoria was also observed. On the basis of these observations, the hypothesis is proposed that astrocytes respond primarily to the mechanical disruption consequent to injury and that the response promotes the restoration of the structural integrity of the lesioned tissue.

Animals↗
PubMed1985

6-OHDA-induced ectopia of external granule cells in the subarachnoid space covering the cerebellum. III. Morphology and synaptic organization of ectopic cerebellar neurons: a scanning and transmission electron microscopic study.

The present report describes the ultrastructure, surface morphology, and synaptic connectivity of ectopically placed cerebellar neurons after treatment of newborn rats with 100 micrograms 6-hydroxydopamine (6-OHDA), administered intracisternally. In addition to granule cells which form the majority of ectopic neurons, neurons exhibiting the ultrastructure of basket/stellate cells are found in the subarachnoid space over the cerebellum. The ectopic neurons present an almost complete spectrum of homologous efferent and afferent connections. Parallel fiber synapses are found on thorns of spiny branchlets of Purkinje cell dendrites which also have grown out into the subarachnoid space, and on the somata and dendrites of basket/stellate cells. Many ectopic parallel fibers are seen to pass into the molecular layer of the underlying cerebellar cortex through defects in the pial surface, presumably connecting with intracortical postsynaptic partners. Synapses between ectopic Purkinje cell dendrites and basket/stellate cell axons are also observed; however, the source of these axons remains uncertain. Granule cell dendrites are engaged in glomeruli with mossy fibers. Moreover, ectopic granule cell colonies are densely innervated by noradrenergic fibers. Our results show that the technique of generating ectopia of external granule cells provides an additional model for investigating influences of epigenetic factors on the development of nerve cells.

Animals↗
PubMed1985

Salmonella infection in hairy cell leukemia: report of a case.

A patient with hairy cell leukemia who developed mediastinal mass and fever is described. A CT-guided aspiration of the mass yielded Salmonella tiphymurium. Granulocyte response to infection was intact and could explain the favorable course of this unusual Salmonella infection. Although several reports deal with salmonellosis as a complication of immunodeficiency states, this type of infection is of rare occurrence in hairy cell leukemia.

Humans↗
PubMed1985

Selective destruction of meningeal cells by 6-hydroxydopamine: a tool to study meningeal-neuroepithelial interaction in brain development.

The effects of 6-hydroxydopamine (6-OHDA) on meningeal cells were studied at different ages in conjunction with blockade of the neuronal uptake 1 for catecholamines using nomifensine (NMF) and of the extraneuronal uptake 2 using normetanephrine (NMN). Our results show that maximal numbers of meningeal cells over the cerebellum of the newborn rat are destroyed by a threshold dose of 6-OHDA of 25 micrograms. The morphological characteristics which mark the time course of degeneration of meningeal cells were used to assess the effects of 6-OHDA given in conjunction with either NMF or NMN to differentiate between neuronal (uptake 1) and extraneuronal (uptake 2) effects of 6-OHDA. Uptake of 6-OHDA into meningeal cells and their subsequent degeneration was prevented by pretreatment with NMN but not with NMF. This finding indicates that meningeal cells have uptake 2 capacity but no uptake 1 membrane pump and explains both their uptake of 6-OHDA and their extreme sensitivity to the toxic effects of this drug. Application of this pharmacological regimen using NMF and NMN in conjunction with 6-OHDA thus allows selective destruction of meningeal cells which may be used experimentally to study the contribution of meningeal cells to brain development.

Animals↗
PubMed1985

Meningeal cells are involved in foliation, lamination, and neurogenesis of the cerebellum: evidence from 6-hydroxydopamine-induced destruction of meningeal cells.

In the present paper we report on experiments conducted to find out if there is a positive correlation between the destruction of meningeal cells over the newborn rat cerebellum by 6-hydroxydopamine (6-OHDA) and the subsequent development of abnormalities in cerebellar fissuration, lamination, and granule cell number. Both destruction of meningeal cells and quality and magnitude of 6-OHDA-induced cerebellar defects show the same threshold sensitivity without further dose responsiveness. Blockade of neuronal uptake 1 for catecholamines with nomifensine prevents neither destruction of meningeal cells nor the development of abnormalities in cerebellar structure after 6-OHDA treatment. Blockade of extraneuronal uptake 2 for catecholamines with normetanephrine prevents both destruction of meningeal cells and the development of typical cerebellar abnormalities after 6-OHDA treatment. All three parallel experiments suggest that there is a positive correlation between the destruction of meningeal cells and the development of abnormal cerebellar structure, indicating that meningeal cells are involved in these defective morphogenetic processes, i.e., fissuration, lamination, and cell proliferation in the external granular layer. The preferential localization of defects in cerebellar fissures indicates that, in analogy to the mesenchyme surrounding other epithelia with a branching morphogenesis, the role of meningeal cells could be the production of interstitial collagen which is necessary to stabilize the epithelial basal lamina in the fissures.

Animals↗
PubMed1985

Identification and partial purification of fibroblast growth factor from the brains of developing rats and leucodystrophic mutant mice.

High titres of fibroblast growth factor activity (assessed by mitogenicity for Balb/c 3T3 fibroblast cells in vitro) have been extracted from the brains of foetal and neonatal rats long before myelinogenesis commences, from the brains of hypomyelinated, leucodystrophic, murine mutants and from normal adult rats. Partial purification, by ion-exchange chromatography and gel filtration, indicates that the brain fibroblast growth factor activity from these sources is associated with very similar basic protein fractions. These results, together with the observation that none of the samples of partially purified basic fibroblast growth factor elicits the experimental allergic encephalomyelitis response attributed to myelin basic protein in the rat, suggest that basic fibroblast growth factor is not a degradation product of myelin basic protein.

Aging↗
PubMed1985

[X-ray computed tomography guided surgery. Equipment and procedure for transcutaneous approach to lesions].

Percutaneous needle biopsy of subclinical lesions using computed tomography guidance requires a precise approach, made possible by a simple apparatus for cutaneous detection by metallic indices. This procedure allowed reliable and rapid determination, in the transverse axial plane, of the cutaneous puncture point and possible angulation of the biopsy needle in relation to vertical or horizontal axes.

Adult↗